<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>数组去重</title>
</head>
<body>
    
</body>
<script>    
    let arr = [1, 1, 2, 2, 3, 3, 4, 5, 6]

    // es5方法
    function fn(arr){
        let newArr = []
        for(let i=0; i< arr.length; i++){
            if(newArr.indexOf(arr[i]) == -1){
                newArr.push(arr[i])
            }
        }
        return newArr
    }
    console.log(fn(arr))

    // es6方法
    let newArr = [...new Set(arr)]
    console.log(new Set(arr), newArr)

</script>
</html>